Frequency compensation scheme for stabilizing the LDO using external NPN in HV domain
US7893670B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 2009 |
| Grant date | Feb 22, 2011 |
| Priority date | — |
| Expiry date | Aug 20, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F1/575
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A voltage regulator may comprise a regulator output configured to provide a regulated voltage, which may be controlled by an error amplifier based on the regulated voltage and a reference voltage. The error amplifier may control a source-follower stage to mirror a multiple of the current flowing in the source-follower stage into an internal pass device. A voltage developed by the mirror current may control an external pass device configured to deliver the load current into the regulator output. A first resistor may be configured to decouple a load capacitor coupled between the regulator output and reference ground, when the load current is below a specified value. A second resistor may be configured to create a bias current in the internal pass device even when the external pass device is close to cut-off region. A third resistor may be configured to counter the effects of negative impedance at the control terminal of the external pass device caused by the current-gain of the external pass device. A compensation capacitor and resistor may be coupled in series between the output of the error amplifier and the output of the voltage regulator to provide frequency compensation for the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.